Overnight, iPhone devotees lined up all across the country to get their hands on the new iPhone 5 – a device being regarded as revolutionary by many due to the iOS upgrade as well as the new aspect ratio of the phone. The smart phone community is expecting major demand for the product over the next year and while the Apple continues to seek perfection in the smart phone field, the specifications of the new device have presented some challenges for developers as they consider how to properly program for the device.

While the device will catch up Apple with the aspect ratio already familiar with Android developers and will make operating system cross compatibility that much easier for ad networks and coders alike, iOS developers will now experience the greatest degree of device fragmentation. With multiple aspect ratios and product lines and just a two week head start, developers now face a dilemma. The iOS platform is more fragmented than ever and the mobile community wonders how the developer-base will respond, and with the short window since the announcements and how quickly is realistic to an application community with over 700,000 titles.

The good news for developers is that Apple will avoid major issues by allowing their developer base to target the 4-inch screen if they so choose, but only as a part of the same app binary from which they target the 3.5-inch screens. Translation, there will be no apps that only run on the iPhone 5′s screen for the present time and Apple has said that they won’t force developers to code for the four inch screen either – at least not yet.

So what happens if the developers don’t code for the four inch screen? The iPhone 5 just takes the standard-sized apps and runs them in a “letterbox” mode with small black bars along the top and bottom of the screen (or sides, if the device is horizontal) much like occurs when an iPhone app runs on the iPad. Also, even if the app isn’t using the real estate, the iOS system elements can according to TechCrunch.

One nice side effect of the letterboxing is that the iOS system elements can still use the larger screen. So, for example, when Push Notifications come in, they flip down from the top of the screen and settle perfectly above the 3.5-inch app (as opposed to on top of it).

Serendipitous though as that feature may be, the letterbox app will be remembered two years from now a design shim that many companies who entrust their apps to developers will look to get away from as fast as possible. Progress is always the mantra of the technology community, so one would expect that while there will be a cross-over period, in time most developers and their financial backers will look to target the 4 inch screens for their device.

It’s been reported by some of the teams who were able to do advance coding before the announcement of the iPhone 5 and iOS 6 that it wasn’t particularly demanding to upgrade existing design and code for the new interface. Since that time though, many publications sought out developers in the field to get their independent reactions to the changes, and while overall most of the developers contacted are enthusiastic about the added screen space, making changes, especially in elaborate apps will take thought and time.

“The introduction of a new aspect ratio is not quite as simple as Apple pictures it, in my opinion,” Marco Tabini told TheNextWeb.com in a recent article “Apps that have complex layout will have to be rethought, and in some cases there could be significant work involved,” according to Tabini.

And Tabini is exactly right, in apps which rely upon Apple UI elements (like lists or text or drawing surfaces) the change will be relatively easy, but the in ground-breaking apps with revolutionary interfaces outside the standard Apple UI major code changes to properly display the new version might be required.

In the end, the iPhone 5 and iOS 6 will propel Apple even farther forward in a market where they have been gaining confidence over Android, most notably in the emerging enterprise space acccording to a recent Appcelerator/IDC survey. The new aspect ratio will present some initial design problems for many developers while mobile consumers cross over from the traditional iPhone aspect ratio to the new one, but it’s momentum is inevitable and developers should expect to build the fragmentation contingency into future projects.